R Packages for Risk Assessment

Régis Pouillot and Marie Laure Delignette-Muller

Two R1 packages specifically developed to help risk assessors in their projects are now available.

The first package, "fitdistrplus", gathers graphical and statistical tools for choosing and fitting a parametric univariate distribution to a given dataset. The data may be continuous or discrete. A major interest of this package lays in its ability to deal with right-, left- or interval-censored continuous data as is frequently obtained when analytical methods have a limit of detection or a limit of quantification. Various censoring thresholds may be present within a dataset. Bootstrap procedures then allow the assessor to evaluate and model the uncertainty around the distribution parameters and to transfer this information into a quantitative risk assessment model.

The second package, "mc2d", helps to build and study two dimensional (or second-order) Monte-Carlo simulations in which the estimation of variability and uncertainty in the risk estimates is separated. This package easily allows the transfer of separated variability and uncertainty along a chain of conditional mathematical and probabilistic models.

These packages are mainly suitable for users with an intermediate experience with R.

Downloads

“fitdistrplus” package

“mc2d” package

Peer review publication

R. Pouillot, M.-L. Delignette-Muller. Evaluating variability and uncertainty separately in microbial quantitative risk assessment using two R packages. International Journal of Food Microbiology, 2010, 142(3): 330-340

For more information please contact: M.-L. Delignette-Muller or R. Pouillot

1. R is an open-source integrated suite of software facilities for data manipulation, calculation, and graphical display, which is extended by a large collection of packages in which up-to-date statistical methods are implemented (R Development Core Team, 2009)